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Commit ab42d9ee authored by Yuchung Cheng's avatar Yuchung Cheng Committed by David S. Miller
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tcp: refactor CA_Loss state processing 



Consolidate all of TCP CA_Loss state processing in
tcp_fastretrans_alert() into a new function called tcp_process_loss().
This is to prepare the new F-RTO implementation in the next patch.

Signed-off-by: default avatarYuchung Cheng <ycheng@google.com>
Acked-by: default avatarNeal Cardwell <ncardwell@google.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9b44190d

net/ipv4/tcp_input.c

+26 −16
Original line number Original line Diff line number Diff line
@@ -2664,6 +2664,30 @@ static void tcp_enter_recovery(struct sock *sk, bool ece_ack) 
	tcp_set_ca_state(sk, TCP_CA_Recovery);

	tcp_set_ca_state(sk, TCP_CA_Recovery);

}

}





/* Process an ACK in CA_Loss state. Move to CA_Open if lost data are

 * recovered or spurious. Otherwise retransmits more on partial ACKs.

 */

static void tcp_process_loss(struct sock *sk, int flag)

{

	struct inet_connection_sock *icsk = inet_csk(sk);

	struct tcp_sock *tp = tcp_sk(sk);



	if (!before(tp->snd_una, tp->high_seq)) {

		icsk->icsk_retransmits = 0;

		tcp_try_undo_recovery(sk);

		return;

	}



	if (flag & FLAG_DATA_ACKED)

		icsk->icsk_retransmits = 0;

	if (tcp_is_reno(tp) && flag & FLAG_SND_UNA_ADVANCED)

		tcp_reset_reno_sack(tp);

	if (tcp_try_undo_loss(sk))

		return;

	tcp_moderate_cwnd(tp);

	tcp_xmit_retransmit_queue(sk);

}



/* Process an event, which can update packets-in-flight not trivially.

/* Process an event, which can update packets-in-flight not trivially.

 * Main goal of this function is to calculate new estimate for left_out,

 * Main goal of this function is to calculate new estimate for left_out,

 * taking into account both packets sitting in receiver's buffer and

 * taking into account both packets sitting in receiver's buffer and
@@ -2710,12 +2734,6 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, 
		tp->retrans_stamp = 0;

		tp->retrans_stamp = 0;

	} else if (!before(tp->snd_una, tp->high_seq)) {

	} else if (!before(tp->snd_una, tp->high_seq)) {

		switch (icsk->icsk_ca_state) {

		switch (icsk->icsk_ca_state) {

		case TCP_CA_Loss:

			icsk->icsk_retransmits = 0;

			if (tcp_try_undo_recovery(sk))

				return;

			break;



		case TCP_CA_CWR:

		case TCP_CA_CWR:

			/* CWR is to be held something *above* high_seq

			/* CWR is to be held something *above* high_seq

			 * is ACKed for CWR bit to reach receiver. */

			 * is ACKed for CWR bit to reach receiver. */
@@ -2746,18 +2764,10 @@ static void tcp_fastretrans_alert(struct sock *sk, int pkts_acked, 
		newly_acked_sacked = pkts_acked + tp->sacked_out - prior_sacked;

		newly_acked_sacked = pkts_acked + tp->sacked_out - prior_sacked;

		break;

		break;

	case TCP_CA_Loss:

	case TCP_CA_Loss:

		if (flag & FLAG_DATA_ACKED)

		tcp_process_loss(sk, flag);

			icsk->icsk_retransmits = 0;

		if (tcp_is_reno(tp) && flag & FLAG_SND_UNA_ADVANCED)

			tcp_reset_reno_sack(tp);

		if (!tcp_try_undo_loss(sk)) {

			tcp_moderate_cwnd(tp);

			tcp_xmit_retransmit_queue(sk);

			return;

		}

		if (icsk->icsk_ca_state != TCP_CA_Open)

		if (icsk->icsk_ca_state != TCP_CA_Open)

			return;

			return;

		/* Loss is undone; fall through to processing in Open state. */

		/* Fall through to processing in Open state. */

	default:

	default:

		if (tcp_is_reno(tp)) {

		if (tcp_is_reno(tp)) {

			if (flag & FLAG_SND_UNA_ADVANCED)

			if (flag & FLAG_SND_UNA_ADVANCED)